Timing mechanism



May 4, 1948. E, J, Fix 2,440,677

TIMING MECHANISH Filed March 7. 1939.

lnveT-LLn-r Buganal-p1x b. lib-Y AiJcmv zyE Patented May 4, 1948 TIMING MECHANISM Eugene J. Fix, Philadelphia, Pa., assignor'to the United States of America as represented by the Secretary of War Application March 7, 1939, serial No. 260,311

\ (o1. 1oz-s4) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 1 Claim.

l The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

, This' invention relates to the timing mechanism of mechanical time fuses of the type wherein the period of running of the clockwork train or other timing mechanism is controlled aby an oscillative escapement balance or lever having a straight length hair spring associated therewith for controlling the frequency of oscillation thereof. More particularly the invention relates to a method and means for very accurately controlling the effective working length of the hair spring.

It has not been uncommon in the art heretofore to employ a straight length hair spring with means for regulating the effective working length of the spring, but so far as I am aware, the regulation has always been effected on one leg of the spring.

I have discovered that the regulation of one leg only of a straight length hair spring may introduce factors which disturb the uniformity of action required of, and potentially present in the hair spring, with resulting reduction in the precision with which the fuse functions.

Having discovered the inaccuracies which prior hair spring regulators may introduce in the functioning of the clockwork train or timing mechanism of a mechanical fuse it is an object of my invention to provide a hair spring regulator mechanism capable of being adjusted to utilize the full potential uniform action of a straight length hair spring for any required effective working length of the spring.

It is a further object of the invention to so position the escapement balance or lever, and straight length hair spring associated therewith, relative to the axis of rotation of the fuse in a manner that will be operative to neutralize centrifugal effecton the balance and hair spring due to rotation of the fuse;y and then provide a hair spring regulator mechanism functional at once, to modify the effective working length of the hair spring and maintain centrifugal effect thereon neutralized.

It is a still further object of my invention to provide a regulator mechanism for a straight length hair spring wherein the effective Working length of either leg of the hair spring may be adjusted to compensate for inherent non-iso chronous characteristics of the spring lengths constituting the legs. f

The specific nature of the invention as well as other objects and advantages thereof will clearly vappear from a, description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a plan view of the hair spring regulator mechanism disposed in operative relation to the hair spring;

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1;

Figs. 3 and 4 are sectional views showing details of the adjusting block and means for retaining the adjusting screw in the supporting plate or member respectively.

Referring to the drawings a plate or member I is provided as a convenient element for supporting the oscillative escapement balance or lever 2, straight length hair spring 3, and hair spring adjusting mechanisms generally indicated at 4.

The plate or member l may be the base or other plate of a plurality of plates comprising the supporting frame for the fuse mechanism and is recessed and/or provided with openings generally indicated at 5 for the accommodation of elements unrelated to the present invention, and therefore, not shown. The central portion of the plate is provided with a bearing support 6 upon which the escapement balance or lever 2 is mounted for oscillation. The supporting axis of the bearing support 6 is so chosen that it will substantially coincide with the axis of rotation of the fuse when and if attached to a rotating projectile. In the embodiment shown, and for convenience only, the member or plate I is related to the remainder of the fuse structure in such manner that its geometric center substantially coincides with the axis of rotation of the fuse.

Escapement balance or lever 2 has integral therewith or otherwise suitably affixed thereto an arbor 'l mounted with one of its ends in the bearing support 6 for oscillation. The other end of the arbor I may be mounted in a bearing, not shown, to ensure oscillation of the arbor on its axis. The escapement balance 2 preferably comprises a lever, having the usual escape pallets 8 and 9 adapted to cooperate with the escape-wheel of a clockwork train or timing mechanism, not shown, to control the rate of running thereof. The lever 2 is secured to the arbor 1 intermediate its ends and has arms I 0, II, respectively, extending from the position of securement to the arbor in substantially equi-distant opposed relation. It will be understood, however, that any oscillatable balance, of utility for the purpose,

may be used for the lever shown in the preferred embodiment.

effective working length of the legs I3, I4 of thek spring comprises adjusting blocks I5 arranged for movement in guideways or grooves I8 below and parallel with the spring and suitable means for effecting movement of the blocks.

The guideways or grooves I8 are identical in construction and each comprises an elongated opening or groove I1 within the portion of plate I generally indicated at 5, terminating outwardly adjacent the periphery of plate I in an outwardly flared portion I8 for a purpose to be describedl hereinafter. Where a plate I of the character above described is employed the guideways may be disposed diametrically of the plate as disclosed in Fig. 1.

I8 of guideway I'I. A retaining element 28 of general T-shape having a cut-away section in the stem of the T is :snugly tted with the stem between the corners of the flared portion I8 and driven to a position where the arms of the T engage the surface of plate I adjacent the corners of the flared portionl I8.

In the latter position of the retaining member 28 the surface of the stem of the T defining the cut-away portionwill be engaged or a sufllcient part thereof will be engaged within groove 28 to prevent axial movement of the screw upon rotation of the same. By this means it should be apparent that I have devised simple means for easily assembling the screws 23 and adjusting blocks I5 and for moving the blocks I5 longitudinally of the guideways I1 upon rotation of the screws 23 to adjust the effective working length of the legs of the hair spring.

Although I have shown a flared out portion I8 of the guide I'I for retaining the element 28 in operative position, this particular embodiment should not be construed as limitative since any Adjusting blocks I5 are each identical in construction and comprise a body portion I9 of general T-shape section slidingly fitted in a guideway or groove portion I'I with the stem or body portion of the section engaging the opposed side walls defining the groove and the lateral arms. or webs of the section engaging the surface of plate I on opposed sides of the groove.- A projection 28 extends from the body portion I9 of each adjusting block to and above the legs of the hair spring and each projection is provided with a suitable opening, here shown as a slit 2I, for receiving the corresponding leg I3 or I4 of the hair spring. The body portion I9 of each adjusting block I5 is pierced and threaded at 22 for receiving the threaded end portion 24 of an adjusting screw 23.

Each adjusting screw 23 has an end portion 24 suitably threaded to cooperate in threaded engagement with the threads at 22 in the body I9 of an adjusting block I5. Also each adjusting screw 23 has an elongated head portion 25 of uniform diameter which is provided adjacent the threaded portion 24 with a circumferential extending groove 26 for a purpose later described.

To provide a means for easily assembling the adjusting blocks I5 and adjusting screws 23 in proper relative disposition with respect to plate I the latter is suitably pierced or otherwise formed with passages 21 leading inward from the periphery of the plate and terminating in the flared ends I3 of the guideways I'I. An adjusting screw 23 is inserted in each passage 21 with the threaded end 24 foremost and threadedly engaged at 22 with the body I9 of an adjusting block I5 in proper position in a guideway I'I. After threaded engagement has been ellected between an adjusting block I5 and adjusting screw 23 the elements are so positioned in a guideway I1 that the circumferential groove 26 in the head 25 of the adjusting screw 23 is aligned with the flared portion properly shaped slot or groove may serve the purpose, although not as easily formed or machined. Moreover the method described of assembling the adjusting blocks I5 and adjusting screws 23 need not be as above outlined, for in those cases where the threaded portions 24 of the adjusting screws 23 are suillciently short the adjusting screws may be threadedly engaged with the adjusting blocks and the assemblies inserted in proper position in the guideways I1 with the heads 25 of the adjusting screws located in the passageways 2'I in position to receive the retaining element 28. f

Having now particularly described what at present appears to me as a preferred embodiment of my invention what I claim and desire to secure by Letters Patent of the United States is:

In a mechanical time fuze comprising a plate having a radial slot, mountings for an escapement lever hair spring slidably mounted in said slots and screw means carried by said plate and engaging said mountings for adjusting the same, retaining means for said screw means comprising relatively thin members of general T-shape profile, having a recess in the stem of the T received in circumferential grooves in the screw means, and an enlarged portion in the slot receiving the retaining member and holding the same against slotwise motion.

EUGENE J. FIX.

REFERENCES CITED The following references are of record in the file of this patent:

UITED STATES PATENTS Number Name Date 163,181 Gill May 11, 1875 1,614,537 Pantoflicek Jan. 18, 1927 FOREIGN PATENTS Number Country Date 284,186 Great Britain Jan. 26, 1928 284,968 Great Britain Feb. 9, 1928 

